Question

我正在下载一个JSON文件，我已将其检查为带有“ https://jsonlint.com”的有效JSON到文档目录。然后，我打开文件并再次检查它，它显示为无效JSON。那怎么可能？这是代码：

let destination: DownloadRequest.DownloadFileDestination = { _, _ in
        var documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]

        documentsURL.appendPathComponent("analysis."+pathExtension)
        return (documentsURL, [.removePreviousFile])
    }

Alamofire.download("http://www...../analysis.json", to: destination).response { response in
        if response.destinationURL != nil {
            print(response.destinationURL!)

            let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
            let documentsDirectory = paths[0]

            let path = documentsDirectory + "/analysis.json"

            if JSONSerialization.isValidJSONObject(path) {
                 print("Valid Json")
            } else {
            print("InValid Json")     ///// I am getting here "INValid Json" - how is that possible????
            }
        }
    }

Answer 1

因为path是一个字符串，指示文件在系统中的位置，类似于file://path/to/analysis.json。那显然是无效的JSON。

您要检查的是该文件的内容是有效的JSON。试试这个：

Alamofire.download("http://www...../analysis.json", to: destination).response { response in
    guard detinationURL = response.destinationURL else { return }
    guard data = Data(contentsOf: destinationURL) else { return }

    do {
        let jsonObject = try JSONSerialization.jsonObject(with: data, options: [])
    } catch {
        print("InValid Json")
    }
}

附带说明：为什么不使用Decodable？

为什么我下载的JSON文件不再是JSON？

1 个答案: